Lenses and Lights

Oct 25, 2010

It's sort of surprising that with all the attention (and theatrical business) 3D cinema has been receiving for the last several years, there aren't more instructional materials available for the professional cinematographer or editor to get up to speed quickly. There are a lot of websites, particularly of the DIY with two cameras strapped to a rail variety, but precious little hard info that couples theory to practice and is applicable to professional 3D rigs.

The classic book is Lenny Lipton's Foundations of the Stereoscopic Cinema. (out of print, but available for free download here) It's very heavy on theory, but you won't find much on the current state of equipment, as it was published in 1982.

Last year saw the publication of 3D Movie Making: Stereoscopic Digital Cinema from Script to Screen, by Bernard Mendiburu. This is a very up to date volume. Not only is it accessible and easy to read by anyone already familiar with the basics of cinematography, it contains many exercises and experiments you can try, including some that don't require access to a dedicated 3D camera rig.

It includes links to websites and a DVD with many useful examples. I recommend this book to anyone starting out in stereoscopic 3D film production (or even fairly far along the way). For producers and directors new to 3D, the first 3 chapters are particularly helpful. I think this book will become a standard and I wouldn't be surprised if it's picked up as a textbook.

Now there is also a very cool course available as a multi DVD set: Stereo 3D Filmmaking: The Complete Interactive Course. I've been viewing the five discs, and I'm very impressed.First, this obviously wasn't just thrown together quickly to take advantage of the 3D boom. The creators have put real effort into it. They didn't just shoot a lecturer in 3D either. Scenes are selected to specifically show off the technique or effect, and includes interiors with near backgrounds, and exteriors with far backgrounds.

The media files on the disc are all in side by side Quicktimes, and are played using the included Frame Forge StereoPlayer. I was viewing on a MacBook, and it was very easy to view, and some of the least amount of ghosting in color anaglyph I've seen on a computer. (partly because they reduced the color saturation a lot). If you have a 3D monitor that can interpret the side by side files directly then you can view the DVD with the glasses that fit your monitor type, polarized or shutter glasses.It includes not just good examples, but bad examples too, so you can see exactly how screen plane violations and too much divergence get you into trouble. More to the point, there is so much about 3D that is difficult to explain well in a book, without clear visuals from multiple viewpoints, such as "dynamic floating windows". Each chapter illuminates each instructional point with not just samples shots, but also diagrams from the side or above and graphic schematics of the scene. I particularly liked the section on the importance of higher resolution for good stereo photography--it made it very clear how compression can lose the small detail that is so important for creating depth that goes beyond making layers, to depth that appears rounded and life like.

I've almost forgotten one of the best features of the package, the Stereo 3D Lab, which uses the Frame Forge Pre Visualization program. This lab comes complete with it's own set of audio guided lessons, only here, you can manipulate the controls on a virtual camera rig, either a side by side rig or a beamsplitter mirror rig. The view from the camera is simulated and updated instantly, so you can experiment with differing interaxials and convergences, angles of view, distances, etc. Very cool.

At this point, I'm supposed to say, but wait there's more-- 3 DVDs that are just interviews with leading people in stereoscopic production. At first I thought these would be filler, but I got a lot out of them.

At US$350, this is not cheap, nor an impulse buy for most people. But I think it's worth it. Not only is it less expensive than an actual hands on course, it is 950 minutes, or almost 17 hours of material! Plus you don't have to travel to where a course is being given. For someone who has been asked to plunge into 3D filmmaking for the first time, or for someone who is already on their way with a 3D project, and still knows they have a lot catch up on, this will be a great help. The best combination would be if one could view this DVD course simultaneous with having accessing to a 3D camera or rig or monitor, so you could try out the examples on your own right away. This combined with a hands on course, or combined with access to a 3D rig for a couple of days, would be ideal. Of course you could try out many of the examples here by using side by side video cameras, if you also have a way to capture and view the images you create in 3d. It's not ideal, but it would be great at really experiencing all the steps in the process.

Feb 16, 2009

Professional television camera history has two main lines: the gradual shrinking of the camera as it became more versatile and self contained; and a progression of sensors from large insensitive tubes to smaller, much more sensitive tubes and finally to very small, very sensitive solid state chip imagers. Cameras that contained their own recording mechanisms did not appear until the early 1980s.

Early studio television camera -- Gray box on right is the lens, gray box on top is the Viewfinder, sides are lowered to show internal electronics.

At the beginning, these cameras were very large devices, almost always in two sections. The camera section held the lens and tube pre-amps and other necessary electronics, and was connected with a large diameter multi-core cable to the rest of the camera electronics, usually mounted in a rack. The rack would be in a separate room in the studio, or in a remote truck. The camera head alone could not generate a video picture signal on its own. The video signal was output from the rack unit to the rest of the studio for switching and transmission. By the fifties, electronic miniaturization had progressed to the point where some monochrome cameras could operate stand alone and even be handheld. But the studio configuration remained, with the large cable bundle transmitting the signals back to the CCU (Camera Control Unit). The CCU in turn was used to align and operate the camera's functions, such as exposure, system timing, and video and black levels.

The first color cameras (1950s in America, early sixties in Europe), notably the RCA TK-40/41 series, were much more complex with their three (and in some models even four) pickup tubes, and the size and weight drastically increased. Handheld color cameras did not come into general use until the early 1970s, and the first ones were two pieces, a camera head shoulder unit that held the lens and tube section, and a backpack unit. The Ikegami HL-33 was the first of this type, but was followed a up by one piece cameras. These one piece cameras, (The HL-77 from Ikegami and the TK76 from RCA) made possible, in combination with portable 3/4" U-matic VCRs, the introduction of Electronic News Gathering (ENG), which very rapidly replaced the 16mm film cameras that had been the dominant method for capturing news events. This established the standard operation in the field of a two person news crew, one operating the camera, and one carrying the shoulder strapped U-matic recorder and a boom microphone. The control layout for the camera's most important functions was also established with these cameras, and continues to define an ENG camera to this day.

In the early 80s, the first cameras with on board cameras were brought to the market. The far more successful of these used the Betacam recording system. At first these cameras used pickup tubes, and the recorders were of the removable type. Models with CCD imagers came on the scene in the mid-80s. These brought multiple benefits. They were much more stable and less prone to drift than tube cameras, and didn't require a warm up or calibration time at the beginning of the day. They also were not prone to image burn in or streaking caused by bright lights. The early models did not have the resolution or color quality of their tube counterparts, but successive models quickly pulled ahead of tube technology. Eventually, cameras with the recorder permanently mated to the camera head became the norm for ENG.

Studio camera technology did not stand still during this period. The camera electronics shrunk, and CCD imagers replaced the pickup tubes. The thick multi-core cables connecting the camera head to the CCU were replaced in the late seventies with triax connections, a slender video cable that carried multiple video signals, intercom audio, and control circuits, and could be run for a mile or more. As the camera innards shrunk, the electronics no longer dictated the size of the enclosure. But the box shape remained, as it was necessary to hold the large studio lenses, teleprompters, studio viewfinder, and other paraphernalia needed for studio and sports production. Electronic Field Production cameras were often mounted in studio configurations inside a mounting cage. This cage supported the additional studio accessories.

In the late 90s, as HDTV broadcasting commenced, HDTV cameras suitable for news and general purpose work were introduced. Though they delivered much better image quality, their overall operation was identical to their standard def predecessors. New methods of recording for ENG cameras were introduced to supplant tape. Ikegami and Avid introduced EditCam in 1996, based on interchangeable hard drives. Panasonic introduced P2 cameras. These recorded a DVCPro signal on interchangeable flash card media. Several other databased recording systems were introduced, notably XDCam from Sony, and as of 2009, it remains to be seen what will become the predominant method of camera media for professional use in the 2010s.

What's the difference between the big shoulder cameras pros use, and small handheld camcorders? Here's a piece I edited on Wikipedia that I liked so much, I thought I'd reprint it here.

Though by definition, ENG (Electronic News Gathering) video cameras were originally designed for use by news camera operators, these have become the dominant style of professional video camera for most uses, from shooting dramas to documentaries, from music videos to corporate training. While they have some similarities to the smaller consumer camcorder, the following differences should be noted:

* ENG cameras are larger and heavier, and usually supported by a shoulder stock on the cameraman's shoulder, taking the weight off of the hand, which is freed to operate the lens zoom control. The weight of the cameras also helps dampen small movements. * 3 CCDs are used instead of one, one for each primary color * They have interchangeable lenses. * All settings, white balance, focus, and iris can be manually adjusted, and automatics can be completely disabled. * The lens is focused manually and directly, without intermediate servo controls. However the lens zoom and focus can be operated with remote controls in a studio configuration. * Professional connectors - BNC for video and XLR for audio. There are at least two XLR audio inputs. * A complete timecode section is available, allowing time code presets; and multiple cameras can be timecode-synchronized with a cable. * "Bars and tone" will be available in-camera (the color bars are SMPTE (Society of Motion Picture and Television Engineers) Bars, a reference signal that simplifies calibration of monitors and setting levels when duplicating and transmitting the picture. * Recording is to a professional medium like some variant of Betacam or DVCPRO or Direct to disk recording or flash memory. If as in the latter two, it's a data recording, much higher data rates (or less compression) are used than in consumer devices. * The camera is mounted on tripods and other supports with a quick release plate. * A rotating behind the lens filter wheel, for selecting an 85A and neutral density filters. * Controls that need quick access are on hard physical switches, not in menu selections. * Gain Select, White/Black balance, color bar select, and record start controls are all in the same general place on the camera, irregardless of the camera manufacturer. * Audio is adjusted manually, with easily accessed physical knobs.

Sep 12, 2008

The great thing about all the new camcorders out there is you don't have to be expert in the underlying tech to get a great result. Here are some simple tips to maximize the performance out of these small wonders.

First—Get Close - Television isn't quite the close-up medium it used to be, what with the popularity of big screens everywhere. But web video sure is. Get Close! Not chin to forehead close, but upper torso or head and shoulders close. People want to see you, not the junk in the background. If your camera has a zoom, backing the camera up and zooming in, is much more flattering to your features than placing the lens close to your face.

Second — Avoid Backlighting - Windows make horrible backgrounds. Daylight can be 800 times brighter than indoor light, and your camera can't cope. So your subject won't look like a silhouette set your camera so the daylight is coming from the side or behind the camera, but the window isn't visible in the picture.

Third — Minimize Noise - Good sound makes video look better! Web videos sound echo-ey and noisy, because the microphone is on the camera, and not close to the person's mouth. Check to see if your camcorder has an external microphone input. An inexpensive microphone from a Radio Shack or an electronics store that has a good camcorder dept. will work much better than the mike on the camera. A lapel mike like the one shown here is perfect.

Fourth—Use a Tripod - Steady does it! When using a camcorder, avoid hand-holding. Web compression software works better on a steady image, and a stable shot looks more professional all around. You can use a tripod, or even place the camera on a steady flat surface. On top of a box on a table works fine. The camera should be at the same height as your face. If cameras seem to make people look ten pounds heavier, shooting from below doubles that effect!

Fifth—Brighten Up! - The low light ability of modern cameras is astonishing. But if the picture looks grainy or blurry you may need more light. Or you may have plenty of light, say from overhead fluorescents, but everything looks flat. Indirect soft light coming in from a window to the side and to the front of the face, almost always gives a very pleasing look. (But not direct sunlight falling on the face -- and with care not to let the window itself show in the picture!)Sixth—Move With Caution - The zoom lens is not a garden hose. Moving the camera around and zooming in and out will just give the audience motion sickness and be very hard to edit later. Hold -- roll tape -- pause tape, frame the next shot. If you’re not able to use a tripod, hand-held can work, thanks to cameras with anti-shake features. It's easier to handhold if you stick with a wide angle, brace against a wall or doorjamb.

Seventh—Lots of Variety - Insert shots! Close-ups and cut-aways are the meaty bites of the video stew. Get lots of detail shots of whatever you are describing verbally. Not only are they informative, insert shots break up the monotony of the single talking head shot. They’re invaluable as cut-aways when you need to shorten the video, and cover over the jarring jump in the edit. Hold each shot for ten seconds. It’s a lot easier to edit a shot shorter, than it is to make it longer.

Eighth—The Camera Sees Differently Than You Do - Don’t get the blues. Watch out for your scene looking overly red or too blue. It’s the result of mixing different kinds of light, such as sunlight with tungsten or fluorescent bulbs. Stick to one light source, so your camera's automatic function can balance to that. If you’re still having trouble, check your camera manual, looking for the section on how to set the white balance. Usually it’s a menu item, with Sun, cloudy, bulb or fluorescent tube icons representing different color casts.

Ninth—Not Everyone Can Be Woody Allen - If you're the one in front of the camera it's hard to do a good job behind the camera. Work with an associate who can both operate the camera, and give you feedback on your performance. Rehearse on tape, watch the result together, see what works, drop what doesn't.

Tenth—The Word Comes First - Write out what you plan to say, even if you're not going to read it word-for-word on camera. Writing it out organizes your thoughts, and helps maintain focus on the subject. Rehearse-out all those distracting "uhms" and "you-knows."